Objective To analyze the factors related to surgical caused infections in children for reducing the infection of operative site.Methods A total of 120 case-times of operation in this hospital were selected.The dynamical air colony number and colony number of surgical instruments were performed the dynamic monitoring.The bacterial colony in air and surface of operative instruments were performed the bacterial species analysis.Results The dynamical air colony number in class 100,1 000,10 000 operating room all presented as "N" character pattern distribution;at 1 h after operation beginning,the variation of air colony number in class 100 operating room was significantly higher than that in class 1 000 and 10 000 operating rooms(P＜0.05).The surface colony increase rate of sterile towel wrapped sterile operating instruments was significantly slower than that of the operating instruments directly exposing to air(P＜0.05).The surface colony increase rate of operating instruments scrubbed by 1％ povidone-iodine was significantly slower than that of operating instruments without scrubbing bloodstain and with scrubbing bloodstain by normal saline(P＜0.05).The bacterial species distribution in operating room air was consistent with that in operating instrument surface.Conclusion The operation caused infection in children is significantly correlated with the operating room bacterial colony number and operation time.